The present invention relates an electromagnetic drive system for opening and closing intake valves and exhaust valves of an internal combustion engine for automobiles.
A Japanese Patent Provisional Publication No. 8-21220 discloses a typical electromagnetic drive system constituted by an electromagnetic drive mechanism and a control unit. The electromagnetic drive mechanism is basically constituted by an armature directly connected to an intake valve, a pair of electromagnets and a pair of springs. The control unit receives information indicative of an engine operating condition from various sensors and outputs a control current to the electromagnetic drive mechanism according to the engine operating condition indicative information. The electromagnets are alternately energized and de-energized to repeatedly open and close the intake valve according to the engine operating condition indicative information.